Isolation of downhole environments depends on the deployment of a downhole tool that effectively seals the entirety of the borehole or a portion thereof, for example, an annulus between a casing wall and production tube. Swellable packers are particularly useful in that they are capable of generating a contact force against a nearby structure when exposed to one or more downhole fluids. Compared with mechanically setup packers and inflatable packers, fluid-swellable packers are easier to set up. However, as the oil and gas industry is shifting towards high temperature and high pressure applications, downhole fluids frequently contain heavy brines based on halides of multivalent cations. Heavy brines tend to decrease the amount of swelling as well as the packers' swelling rate. Accordingly, new swellable sealing systems and methods that improve upon swelling efficiency under a variety of conditions would be readily received in the art.